Damping plate for EMT140 style plate reverbs

[saint gillis]

Building a diy plate reverb is an ambitious project
Mine has been stuck for 6 years because I was not brave enough to start making a damping plate

In my experience this is THE really discouraging part of the project

Meanwhile I've found this document which is a kind of "Everything You Always Wanted to Know About Plate Reverbs (But Were Afraid to Ask)" :
https://www.bbceng.info/ti/eqpt/EMT140.pdf

My first question is : What absorptive material would you use for the damping plate?
- In the document above they say : "a form of compressed glass fibre 0-8 mm thick in numerous small pieces, which are stiffened by a strip connected on the back, to a framework etc.."
- I've read somewhere else that asbestos was used
- I've read on gearspace that some valuable people advised Shasta or Rokfon ceiling tiles

So.. what would you use for the damping plate ?

 

[Rob Flinn]

The original EMT damping plates are what look like suspended ceiling tiles glued to a lightweight aluminium frame.

 

[dmp]

Search for the PDFs by Jim Cunningham, maker of the Ecoplate

"The damping plate is one of the critical parts of any plate system. In
order to adequately control the reverberation time, it must have what the
inventors called ”flow resistance”, This is supplied by using typical 2’ x 4’
ceiling tiles that have a plastic back with “pin perfs”, that is a large number
of small holes in the plastic backing. DO NOT USE A PLYWOOD
BACKING TO MOUNT THIS MATERIAL Mount as shown in the drawing.
We would urge any builder to get the EMT patents from the www.uspto.gov/
Pat. No. 2923369. Also a story on the development of the ECOPLATETM
is available by email from [email protected]."

 

[saint gillis]

Search for the PDFs by Jim Cunningham, maker of the Ecoplate

"The damping plate is one of the critical parts of any plate system. In
order to adequately control the reverberation time, it must have what the
inventors called ”flow resistance”, This is supplied by using typical 2’ x 4’
ceiling tiles that have a plastic back with “pin perfs”, that is a large number
of small holes in the plastic backing. DO NOT USE A PLYWOOD
BACKING TO MOUNT THIS MATERIAL Mount as shown in the drawing.
We would urge any builder to get the EMT patents from the www.uspto.gov/
Pat. No. 2923369. Also a story on the development of the ECOPLATETM
is available by email from [email protected]."

Good information, do you have the document? I didn't find this particular one

 

[dmp]

Here it is